‘Vaguely’ because the location is never really referred to and, though much of the setting looks like San Francisco, much of it is clearly southern California.

The mock-Tudor mansion of Julia Rainbird (Cathleen Nesbitt), where the plot kicks off with fake medium Blanche (Barbara Harris) offering to find an estranged nephew, is in South Pasadena.

The paths of small-time hucksters Blanche and George (Bruce Dern) cross with professional kidnappers Arthur Adamson (William Devane) and Fran (Karen Black). The kidnappers’s home, with its secret chamber, is supposedly ‘1001 Franklin Street’. It’s actually 2240 Sacramento Street at Buchanan Street, San Francisco. A stretch of Buchanan Street, around the corner, with the garage door entrance, was recreated in the studio in Hollywood.

The department store, where George quizzes the Rainbird family chauffeur's daughter, was Bullock's, the 1928 art deco gem in midtown Los Angeles. Although the store has closed, the building lives on as the Southwestern Law School, 3050 Wilshire Boulevard. You can see its exterior in Martin Scorsese’s The Aviator and the 1937 comedy Topper.

The lead takes George to 'Barlow Creek Cemetery', where he discovers the grave of the mysterious ‘Eddie Shoebridge’. The scruffy little graveyard is Pioneer Cemetery in Sierra Vista Park, Sierra Madre Boulevard, Sierra Madre, just northeast of Pasadena. It’s not really so neglected, of course. The tiny cemetery was booked for filming months in advance and allowed to become wild and overgrown.

Back to San Francisco, to find ‘St Anselm’s Cathedral’, where George goes to find the priest, now a bishop, who baptised Eddie Shoebridge. The cathedral, where Hitchcock stages the bravura sequence in which the bishop is kidnapped in full view of his congregation, is Grace Cathedral, 1051 Taylor Street. You might have seen the cathedral on-screen previously in the classic San Fran actioner Bullitt.

George and Blanche are lured out of the city for a bogus meeting, which allows devious Joe Maloney (Ed Lauter) to tamper with the brakes of their car. The out-of-control motor careers hair-raisingly down the vertiginous curves of the Angeles Crest Highway, winding through the mountains of the Angeles National Forest, north of Los Angeles.